upgrade and root after 3.5.4 update

[Yalums]

Hello everyone, it's a pleasure to meet you all in this forum.
Just recently, I managed to downgrade my Boox Note X2 (regional special edition of Note Air2 Plus) from 3.5.4 to 3.5.1, and next upgraded to the 3.5.3 system of Note Air2 Plus (I didn't get the 3.5.3 upx file for Note X2, so I had to go with 3.5.4)
For some specific devices, 3.5.4 really sucks, they completely disabled most fastboot commands, while the new vendor partition got messed up, and the change in refresh mechanism made the original a2 fresh mode almost no longer usable, so I chose to downgrade.
So how did all this happen?

First of all thanks to the geeky users here, I learned that the disabling of the fastboot command is related to the change in the abl partition, so I started by flashing the abl partition of the old version (3.5.1) using adb reboot edl into 9008 mode while booting. Soon, I found that I could flush the rooted boot image in fastboot mode (not fastbootd, but the original fastboot mode where I rebooted to the bootloader). However, at this time, the fastboot mode still can not use the write command, I think this is related to the recovery partition. So, I tried to continue flashing the recovery partition of version 3.5.1 in fastboot mode, and it worked, I was able to directly flash the payload file of version 3.5.3 in fastbood mode!
However, there is another problem here, because of Bootloader AVB (Android Verified Boot 2.0), I needed to manually modify the vbmeta & vbmeta_system image files for systems that are not the current model, so I did that as well. After flashing the full payload.bin, I proceeded to flash the vbmeta and vbmeta_system image files after removing the AVB validation, and I ended up with a working 3.5.3 system!
Thanks for reading, hope this will help you

Translated with DeepL.com (free version)

[richard.black]

Hey!

so I started by flashing the abl partition of the old version (3.5.1) using adb reboot edl into 9008 mode while booting

So, I tried to continue flashing the recovery partition of version 3.5.1 in fastboot mode, and it worked, I was able to directly flash the payload file of version 3.5.3 in fastbood mode

Awesome! I don't have a backup of my previous adb and recovery partitions, is there any I can achieve what you've done?

I needed to manually modify the vbmeta & vbmeta_system image files for systems that are not the current model, so I did that as well.

After flashing the full payload.bin, I proceeded to flash the vbmeta and vbmeta_system image files after removing the AVB validation, and I ended up with a working 3.5.3 system!

Could you share the commands you've used?
I, too, want to have a rooted v3.5.3? or 4? device.
Thanks

[Renate]

I'd venture to say that the deprecation (and degradation) of flash commands in abl is part of the movement to fastbootd in recovery. I believe this is driven by Google?

We're in the future here, folks. Using old software is a bit of a dead end. Admittedly new software is more spin than something that is valuable to you. But it has the potential to be fixed either by the OEM or by hobbyists.

[Yalums]

ah, if there's only need for root the device, you can still use the edl mode, when you get the magisk_boot.img, also flash it in the edl mode is ok. Btw, i use tao1996's DNA Android to remove avb validation and there must be some other methods, if you're interested: https://github.com/Baidaidai-GFWD/An...hing_Knowledge
Just because I'm Note X2 and I wanna flash Note Air 2 Plus's vendor, system and etc, so I removed avb validation, if you require a history version of recovery or abl, please ask for a the same model and in that verson's friend

[Yalums]

Sadly, the pessimistic reality is that future devices shipped after 3.5.1 will not have the “flush to previous abl and recovery” method, so I'm hoping that one of these geeks will come along here or elsewhere and find the connection and make a decipherable method, otherwise we'll just have to take our chances with the edl method of flashing partitions in the future, which always has a much higher risk. always carries more risk.

[Renate]

Originally Posted by Yalums

... otherwise we'll just have to take our chances with the edl method of flashing partitions in the future, which always has a much higher risk. always carries more risk.

I don't find that so. I use EDL all the time for tasks like flashing the system logical partition inside the super partition and never have a problem. And of course you can use the dd command to flash individual partitions from a rooted ADB in either normal system or recovery. Using a flash drive or an internal SD card when available you can flash large things or do updates in recovery when there is not enough free space because data is not mounted. The only really useful thing we lose by fastboot being chopped down is the ability to directly boot an image. Even that is not important because with EDL we can just flash the boot image, reboot and if it bootloops just restore with EDL.

Without EDL and a Firehose loader, yes, we have big problems.